Field
This invention relates to methods and apparatus for encoding and decoding multimedia data such as video data or audio data with error management.
Background
Widespread use of the Internet and wireless communication has increased demand for multimedia services that stream media over the Internet and mobile/wireless channels. In Internet Protocol (IP) networks, video may be provided by a server and may be streamed by one or more wired or wireless clients. Wired connections include dial-up, integrated services digital network (ISDN), cable, digital subscriber line protocols (collectively referred to as xDSL), fiber, local area networks (LAN), wide area networks (WAN) and others. Electronic devices utilizing wireless communications include telephones (e.g., cell phones), personal data assistants (PDAs), hand-held and portable computers, satellite phones and others. In most, if not all of these applications, bandwidth requirements and/or restrictions necessitate that video processing utilize a source encoder incorporating video compression algorithms to analyze, quantify, process and represent video data to convey the maximum information by expending a “minimum” number of bits. Characteristics of such algorithms vary significantly which leads to large scale variations in their performance (such as objective/subjective quality, compression efficiency and bit rate). Characteristics of video processing using compressions algorithms may vary significantly based on content, which may lead to large scale variations in their performance (such as objective/subjective quality, compression efficiency and bit rate).
Wireless channels are prone to errors. A part of transmitted data is “erroneous” if this part of data is lost or corrupt. Because video compression inherently removes redundancy, the compressed data becomes critical. Any erroneous part of this data during transmission impacts reconstructed video quality at the decoder. The impact is aggravated if the erroneous data is part of the reference frame for motion compensated prediction, causing temporal error propagation.
To alleviate the impact on reconstructed video quality due to erroneously received bitstream data, the video decoder processes the received video data to improve video quality. This is referred to as error concealment. Error concealment schemes make use of the spatial and temporal correlation that exists in the video signal.
Currently, several error concealment schemes are available. Depending on the particular circumstances, one error concealment scheme may offer a better result than other error concealment schemes. Therefore, it is desirable to develop a unified error concealment framework that may dynamically choose from a plurality of error concealment schemes the one that is more suitable for a particular concealment task.